1. Field of the Invention
The present invention relates to a surface light source unit with a light guide, and a liquid crystal display device with the surface light source unit.
2. Description of the Related Art
In general, liquid crystal display devices comprise a liquid crystal display panel for displaying an input image, and a surface light source unit for illuminating the panel from behind. The display liquid display panel is supported by the back frame of the surface light source, and has its periphery covered with a cover.
The surface light source unit includes a light source for emitting light, and a light guide for guiding the light emitted from the light source. The light guide and light source are supported by the back frame, and the light source is provided around the light guide. The back frame includes a projection projecting between the light source and light guide to position them. The back frame is formed of, for example, a polycarbonate resin, and the light guide is formed of an acrylic resin.
In the prior art, when an external force is applied to the liquid crystal display device, thereby causing the surface light source unit to, for example, be twisted, the light guide may contact the back frame, thereby generating noise.
To suppress the noise caused when such members as the liquid crystal panel and frame contact each other, a method for imparting an inclined surface to the inner wall of the frame has been proposed (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 2001-4983).
However, even if such an inclined surface is provided, the projection of the back frame for positioning the light guide may well be brought into contact with the light guide, thereby inevitably generating noise.